Connectors for use with polarization-maintaining and multicore optical fiber cables

Abstract

An optical fiber ferrule has a plurality of guide holes therein for guiding a respective plurality of flat-sided fibers at an end of a multifiber optical fiber cable. The fibers' flat sides identify a particular rotational orientation of the fiber. Rotational alignment is achieved by urging the fibers' flat sides against a corresponding reference surface within the ferrule or within an alignment fixture. Also described is a fiber array block having a plurality of V-shaped grooves extending across an outer surface and terminating at an endface. The V-shaped grooves are shaped to guide a respective plurality of flat-sided fibers. A lid is installable across the plurality of V-shaped grooves, over fibers that have been loaded therein.

What is claimed is: 
     
       1. A multifiber ferrule, comprising
 a molded plastic body comprising block-shaped base and head sections, through which there extends one or more guide holes corresponding, respectively, to an equal number of respective polarization-maintaining fibers at an end of a multifiber optical fiber cable, 
 wherein each polarization-maintaining fiber has at least one flat side surface identifying a particular rotational orientation of a fiber transmission axis, such that the fiber transmission axis is alignable to a selected rotational orientation by causing the at least one flat side surface to abut a respective reference surface, 
 wherein each guide hole extends through the ferrule body and is shaped to closely receive a respective polarization-maintaining fiber threaded therethrough, 
 wherein each guide hole is provided with one or more flat side reference surfaces therewithin corresponding, respectively, to the one or more flat side surfaces of a respective polarization-maintaining fiber, such that alignment of the one or more flat side surfaces of each respective polarization-maintaining fiber against the one or more flat surfaces within each corresponding guide hole results in a rotational alignment of each polarization-maintaining fiber to a selected rotational orientation, 
 wherein each guide hole and respective polarization-maintaining fiber are configured to have a close enough fit such that each polarization-maintaining fiber is rotationally confined within its respective guide hole in the selected rotational orientation, and 
 wherein the ferrule body is configured to provide aligned connectorization with a mating structure for each of the respective endfaces of polarization-maintaining fibers installed into the guide holes. 
 
     
     
       2. The multifiber ferrule of  claim 1 ,
 wherein each guide hole and its respective polarization-maintaining fiber have corresponding D-shaped profiles, 
 wherein each polarization-maintaining fiber has a flat side surface extending along its length indicating the rotational orientation of a fiber polarization axis, and 
 wherein each guide hole has a flat side reference surface extending along its length corresponding to the flat side surface of its respective polarization-maintaining fiber. 
 
     
     
       3. The multifiber ferrule of  claim 2 ,
 wherein each polarization-maintaining fiber has a flat side surface extending along its length indicating the rotational orientation of the fiber's slow polarization axis. 
 
     
     
       4. The multifiber ferrule of  claim 2 ,
 wherein each polarization-maintaining fiber has a flat side surface extending along its length indicating the rotational orientation of the fiber's fast polarization axis. 
 
     
     
       5. The multifiber ferrule of  claim 2 ,
 wherein the guide holes are arranged in one or more linear arrays. 
 
     
     
       6. The multifiber ferrule of  claim 5 ,
 wherein the flat reference surfaces of the guide holes in each of the one or more linear arrays are coplanar. 
 
     
     
       7. The multifiber ferrule of  claim 1 ,
 wherein the ferrule is configured as a mechanical transfer ferrule.